Welcome to the site !!
Are your bar clamps 1-1/8" ?? , if not they need to be to use a KTM specific bar , as they are 1-1/8" from the factory , Honda bars are 7/8" , otherwise they won't fit , so you need to confirm that with the sales person and confirm what is actually on your bike , i have used Pastrana FMX High Bars (Pro Taper) on my X with no issues and they are pretty tall , but as mentioned , i have 1-1/8" clamps , the only thing you might have to do (i had to on my 02 450R) was use a (in my case) 450X Galfer Steel Braided Brake Line , as the R brake line was pulled tight across the number plate with higher bars , so you "might" have to use a 250X (or 450X) brake line to not have issues with the line being tight , it bolts up the exact same as the 450/250R lines with the exception of the length , you won't really know that till you install the bars and see where the stock line lays and how tight it is across the front plate ...... other than that , you should not have any issues , with the possible exception of the size bar clamps you may have
